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hand; "but I knew you had too much sense to bide away: denly ?" Bathsheba inquired, the next time that Liddy May I ask what dreadful thing it is that has happened be entered the room. tween you and him?”.
“I think 'twas because two men came just then from “ You may ask ; but I may not tell.”
Casterbridge and began putting up a grand carved tombIn about ten minutes they returned to the house by a stone," said Liddy.The lads went to see whose it was." circuitous route, entering at the rear. Batbsbeba glided “Do you know?” Bathsheba asked. up the back stairs to a disused attic, and her companion “I don't," said Liddy. followed.
(To be continued.) “Liddy,” she said, with a lighter heart, for youth and hope had begun to reassert themselves, “ you are to be my confidante for the present — somebody must be — and I choose you. Well, I shall take up my abode here for a
THE SUN A BUBBLE. while. Will you get a fire lighted, put down a piece of carpet, and help me to make the place comfortable ? Af An American astronomer of great eminence has recently terwards, I want you and Maryann to bring up that little suggested a very startling theory respecting the sun, preiron bedstead in the small room, and the bed belonging to senting that orb to our contemplation as, literally, a mere it, and a table, and some other things. ... What shall I bubble, though a splendid one and of stupendous dimen. do to pass the heavy time away!”
sions. If this theory were only advanced as a speculation, “ Hemming handkerchiefs is a very good thing,” said a crude notion as to what might be, we should not care to Liddy.
discuss it in these pages. But the hypothesis has been “Oh, no, no! I hate needle-work — I always did." based on a very careful discussion of facts, and affords, on « Knitting ?"
the whole, a readier explanation of certain observed appear“ And that, too."
ances than any other which bas been suggested. We pro“ You might finish your sampler. Only the carnations pose, therefore, briefly to describe the pbenomena on which and peacocks want filling in; and then it could be framed the theory is founded, and then to sketch the theory itself, and glazed, and hung beside your aunt's, ma'am."
and some of the most remarkable consequences which must “ Samplers are out of date — horribly countrified. No, be accepted along with it, should it be admitted. Liddy, I'll read. Bring up some books — not new ones. But first, we shall present some of the ideas which very I haven't heart to read anything new.”
eminent astronomers have entertained respecting the con“ Some of your uncle's old ones, ma'am ? "
dition of that glowing surface wbich astronomers call the “ Yes. Some of those we stowed away in boxes." A Solar Photosphere. It will be seen that the bubble theory faint gleam of humor passed over her face as she said : 1 of the sun bas been far surpassed in audacity by former “ Bring Beaumont and Fletcher's Maid's Tragedy ;' and speculations respecting the great central luminary of our the Mourning Bride ;' and — let me see - Night system. Thoughts,' and the Vanity of Human Wishes.'”
Sir. W. Herschel, during the whole course of his obser. “ And that story of the black man, who murdered bis vations of the sun, proceeded on the assumption, wbich wife Desdemona ?' It is a nice dismal one, that would suit | perhaps appears a natural one, that the sun bas a solid you excellent just now."
globe around which lies an atmosphere of a complex nat. “Now, Lidd, you've been ooking into my books, with- | ure. We shall presently describe his strange ideas reout telling me ; and I said you were not to! Ilow do you specting the nature of the solar globe ; but it will be well know it would suit me? It wouldn't suit me at all.”
to quote first bis views as to the atmosphere of the sun, and “ But if the others do ” —
the analogies he recognized between the sun's atmosphere “ No, they lon't; and I won't read dismal books. Why and the earth's. “The earth," he said, in a passage exshould I read dismal books, indeed ? Bring me · Love in plaining his view as to the solar spots, " is surrounded by a Village,' and the Maid of the Mill,' and Doctor Syn an atmosphere composed of various elastic fluids. The tax,' and some volumes of the Spectator.'”
sun also has its atmosphere, and if some of the fluids which All that day Bathsheba and Liddy lived in the attic in i enter into its composiiion should be of a shining brilliancy, a state of barricade ; a precaution which proved to be | while others are nearly transparent, any temporary cause needless as against Troy, for he did not appear in the whicb may remove the lucid iluid will permit us to see the neighborhood, or trouble them at all. Bathsheba sat at the body of the sun tbrough the transparent oner. If an obwindow till sunset, sometimes attempting to read, at other server were placed on the moon he would see the solid times watching every movement outside without much pur- | body of our earth only in those places where the transparpose, and listening without much interest to every sound. ent suids of the atmosphere would permit him. In others
The sun went down almost blood-red that night, and a tbe opaque vapors would reflect the light of the sun with. livid cloud received its rays in the east. Up against this out permitting his view to penetrate to the surface of our dark background the west front of the church-tower - the globe. He would probably also find that our planet had only part of the edifice visible from the farm-house win occasionally some shining fluids in its atmosphere, as, not dows — rose distinct and lustrous, the vane upon the pin- unlikely, some of our northern lights might attract bis no. nacle bristling with rays. Here, about six o'clock, the tice, if they happened in the inenligbtened part of the young men of the village gathered, as was their custom, earth, and were seen by him in his long dark night." He for a game of fives. The tower had been consecrated to goes on to show how the various phenomena of sun spots this ancient diversion from time immemorial, the western can be explained by the theory that they are due to the façade conveniently forming the boundary of the church
occasional and temporary removal of the shining atmos. yard at that end, where the ground was trodden hard and
pbere from parts of the sun. “In the year 1791,” he probare as a pavement by the plavers. She could see the ceeds, “I examined a large spot in the sun, and found it balls flying upwards, almost to the belfry window, and the evidently depressed below the level of the surface ; about brown and black heads of the young lads darting about the third part was a broad margin or plain of considerable right and left, their white shirt-sleeves gleaming in the sun; extent, less bright than the sun, and also lower than its whilst occasionally a shout and a peal of hearty laughter surface. This plain seemed to rise, with shelving sides, up varied the stillness of the evening air. They continued to the place where it joined the level of the surface. How playing for a quarter of an hour or so, when the game con very ill would this agree with the old ideas of solid bodies cluded abruptly, and the players leapt over the wall and bobbing up and down in a fiery liquid, with the smoke of vanished round to the north side behind a yew-tree, which volcanoes, or scum upon an ocean ; and how easily is it was also half behind a beech, now spreading in one inass explained upon our foregoing theory. The removal of the of golden foliage, on which the branches traced black i shining atmosphere, which permits us to see the sun, must lines.
naturally be attended with a gradual diminution on its bor“Why did the fives-players finish their game so sud- ders. An instance of a similar kind we have daily before
us, when, through an opening of a cloud, we see the sky, here discuss the question whetber these solar willow leaves which generally is attended by a surrounding haziness of bave a real existence or not. Suslice it that the evidence some short extent."
on the subject appeared to Sir John Herschel to be demonHe was led by considerations such as these, to conceive strative. * The leaves or scales," be said, “are not arthat the real body of the sun is neither illuminated nor ranged in any order (as those of a butterfly's wings are), heated to any remarkable degree, and may, in fact, be hab but lie crossing in all directions like what are called spills itable. “ The sun, viewed in this light,” he said, “ appears in the game of spillikins; except at the borders of a spot, to be nothing else than a very eminent, large, and lucid where they point, for the most part, inwards, towards the planet, evidently the first, or, in strictness of speaking, the middle of the spot, presenting much the sort of appearance only primary one of our system, all others being truly sec- that the small leaves of some water-plants or sea-weeds do ondary to it. Its similarity to the ot ber globes of the solar at the edge of a deep hole of clear water. The exceedingly system with regard to its solidity, its atmospbere, and its definite shape of these objects; their exact similarity one to diversified surface; the rotation upon its axis, and the fall | another; and the way in which they lie athwart and across of heavy bodies, lead us on to suppose that it is most prob each other (except where they form a sort of bridge across a ably also inbabited, like the rest of the planets, by beings spot, in which case they seem to effect a common direction, whose organs are adapted to the peculiar circumstances of that, namely, of the bridge itself), all these characters seem that vast globe. Whatever fanciful poets may say in mak- l quite repugnant to the notion of their being of a vaporous, ing the sun the abode of blessed spirits, or angry moralists a cloudy, or a fluid nature. Nothing remains but to condevise in pointing it out as a fit place for the punishment sider them as separate and independent sheets, Makes, or of the wicked, it does not appear that they had any other scales, having some sort of solidity. And these flakes, be foundations than mere opinion and vague surmise; but now they what they may, and whatever may be said of the I think myself authorized, upon astronomical principles, to dashing of meteoric stones into the sun's atmosphere, etc., propose the sun as an inhabitable world, and am persuaded are evidently the immediate sources of the solar light and that my observations, and the conclusions I have drawn heat, by whatever mechanism or whatever processes they from them, are sufficient to answer every objection that may be enabled to develop, and as it were elaborat, i hese may be made against it.”
elements from the bosom of the non-luminous fluid in which Before passing from the views of the greatest observa- they appear to float. Looked at in this point of view. we tional astronomer that ever lived, we shall venture to quote i cannot refuse to regard them as organisms of some peculiar yet another passage, to show on what feeble arguments he and amazing kind ; and though it may appear too daring was content to rely, when this favorite theory of his was in to speak of such organizations as partaking of the nature question. He pictures to bimself and bis readers how the of life, yet we do know that vital action is competent to deinbabitants of our moon, and of the moons circling around velop at once heat and light and electricity. These wonJupiter, Saturn, and Uranus, considering the oflices dis- derful objects have been seen by others tban Mr. Nasmyth, charged by those planets, might be led to regard their pri- || 80 that there is no room to doubt of their reality. To be maries as “mere attractive centres, to direct their revolu- seen at all, however, even with the bighest magnifying tions, and to supply them with reflected light in the absence powers our telescopes will bear when applied to the sun, of direct illumination.” “ Qught we not,” he proceeds se. They can hardly be less than a thousand miles in length, riously to demand, “ to condemn their ignorance as pro- and two or three hundred in breadth.” ceeding from want of attention and proper reflection ?' It! It is not a little singular that the two Herschels, among is very true that the earth and those other planets that the ablest reasoners on observed facts, and both highly dishave satellites about them perform all the offices that have tinguished for observational skill, sliould have advanced been named for the inhabitants of these little globes ; but theories so fanciful as the two we have quoted above. On to us who live upon one of these planets, their reasonings no other evidence than the fact that the sun, like the earth, cannot but appear very defective, when we see what a mag. is a rotating globe, the elder llerschel was prepared, we nificent dwelling-place the earth affords to numberless in. / will not say to overlook the intense light and beat of the telligent beings. These considerations ought to make the solar orb, but to invent a protecting envelope, of a nature inhabitants of the planets wiser than we have supposed | utterly unlike that of any material known to men of scithose of their satellites to be. We surely cught not, like ence, whereby the solar inhabitants might be protected them, to say, "The sun' (that immense globe, whose body! from the sun's fiery rays; while the younger llerschel, would much more than all the whole orbit of the moon) | accepting confidently the “solar willow leaves" (much
is merely an attractive centre to us.' From experience doubted by other astronomers), was prepared to regard we can affirm that the performance of the most salutary | them as organisms whose vitality supplies the light and offices to inferior planets is not inconsistent with the dig. I heat emitted by the sun! When theories so startling have nity of superior purposes; and in consequence of such been maintained by the acknowledged chiefs of modern asanalogical reasonings, assisted by telescopic views, which tronomy, we may be content to regard without much surplainly favor the same opinion, we need not hesitate to ad- prise the theory, strange though it seems at a first view, mit that the sun is richly stored with inbabitants."
| that the sun is a gigantic bubble. Sir John Herschel went far beyond his father, however, But we believe that we shall be able to show that the in dealing with the question of the sun's habitability. He bubble theory has very strong evidence in its favor. Let adopted a totally diferent view. Admitting the possible us first consider the facts which suggested it. coolness of the real solar globe, and the consequent possi Very soon after 1 Dr. Huggins bad devised a method by bility of the existence of ordinary forms of life upon it, he which the colored prominences of the sun could be studied nevertheless preferred to regard the true inhabitants of the without the aid of a total solar eclipse, astronomers discovsun, not simply as capable of bearing an intense heat and ered that in many cases the red prominences result from light, but as themselves emitting the chief part of the light veritable solar eruptions. Some prominences, indeed, are and heat which we receive from the sun! This may ap. obviously in a condition of comparative quiescence, floating pear altogether incredible, and, in fact, the terms in which (as it were) like clouds in the solar atmosphere, and either Sir John Herschel expressed the opinion were not quite so remaining unchanged for hours or even for days, or else definite as those which we have just used. Nevertheless, undergoing only very gradual processes of alteration. But we believe our readers, after considering the passages we there are others which are manifestly true jets. It is not shall quote from Sir John Herschel's statement of his merely that the shape of these prominences indicates unviews, will perceive that there can be very little doubt as mistakably that the matter composing them has been ejected to his real opinion.
with great violence from the sun's interior, but several have The surface of the sun, when examined with very pow been watched during the actual process of ejection. They erful telescopes, shows a multitude of bright granulations, i The reference above is to the first detailed statrment of the method by which, according to Nasmyth, are due to the existence of which the prominences were to be seen without eclipse, such xin tient bear
ing date February, 1808, or six months before the method was first successvery bright objects shaped like willow leaves. We do not
have been seen to rise to a great height, and then either to gravitating and compressive energy of the sun's globe subside slowly towards the region whence they have been regarded as a whole. It may serve to give an idea of ejected, or else to bend over like the curved jet of a foun this energy to mention the following circumstance: If an tain, so descending until a complete arch of red matter has atmosphere constituted like ours surrounded the sun been formed.
(which, for the moment, we will regard as a cool body), Accordingly, we find that Zöllner, Respighi, Secchi, and this atmosphere, instead of doubling in density with about others who have studied the sun, have agreed in recognize 3 miles of descent, as happens with ours, would double ing the action of solar eruptive forces in the production of some twenty-seven times in that short distance, so that the jet-shaped prominences.
if at the sun's actual surface the pressure were the same But the most striking evidence of the energy of the sun's as that of the air at our sea-level, then at a depth of 31 eruptive forces was obtained by the astronomer to whom miles (and many of the sun's spots show a depth of two or the Bubble Theory of the Sun is due - Professor Young, three thousand miles) the pressure would be increased of Dartmouth College, Hanover, U. S. He was observing more than six million times, under which enormous action the edge of the sun in October, 1871, having his telescope the air would beyond question be solidified. If we could (armed with a powerful spectroscope) directed upon a suppose that the air were not solidified, then we should long, low-lying band of solar clouds. We say low-lying, have to assume that it became compressed to a density but in point of fact the upper side of the cloud-layer was exceeding that of our air more than six million tiines — fully fifty thousand miles above the sun's surface, the that is, exceeding the density of platinum about four hunlower side being not less than twenty thousand miles dred times. above that surface. The cloud-layer was about 400,000 Now the actual density of the sun is but about one fourth miles in length. Professor Young was called away from | the density of the earth, and is very little greater than the his telescopic work for half an hour at a somewhat inter density of water. Remembering that at the sun's treesting epoch, for he had noticed that a bright rounded | mendous heat vapors and gases could remain as such at & cloud was rapidly forming beneath the larger and quieter pressure very far exceeding that to which we can subject cloud-layer. In less than half an hour be returned, how any gas, and probably when so compressed as to exceed ever; and then, to bis amazement, he found that the great | water in density, it is clear that we must regard the sun cloud had been literally scattered into fragments by an as in the main a gaseous body. It cannot possibly have a explosion from beneath. The small rounded cloud had large solid or liquid nucleus, whatever opinion we may changed in shape, as if the explosion had taken place form as to its having a solid or liquid crust; for if it had through it, and all that remained of the large cloud was a such a nucleus, it would be a much more massive body stream of ascending fragments, averaging about three than we know it to be. As we see, moreover, that it must thousand miles in length and about three hundred in have a solid or liquid crust, we may fairly dismiss the idea breadth. Professor Young watched the ascent of these that it has any solid or liquid nucleus at all. . fragments (each of which, be it noted, had a surface But there is a great difficulty in understanding how a largely exceeding that of the British Isles), and he found globe like the sun, not only glowing throughout with the that before vanishing (as by cooling) they reached a height intensity of its inherent heat, but also manifestly the scene of about 210,000 miles. Moreover, he timed their ascent, of treinendous processes of internal disturbance, can bare and from his time-measurements the present writer was a crust (in the ordinary acceptance of the term) encircling able to demonstrate the surprising fact that the outrusbing its vaporous interior. The phenomena presented by the matter by which the great cloud had been rent to shreds spots show us that the forces acting from within are commust have crossed the sun's surface at a rate of at least petent to burst their way through any existing solar crust; five hundred miles per second!
and any ordinary crust would be reduced to fragments Now, no explosion can occur where there has been no under the action of such forces. Moreover, it is not easy repression. When a volcano, for example, gives vent to to see how a crust thus readily rent asunder and tossed some great eruption, the energy of the eruption is due to on one side could act the part which the solar enclosing and corresponds with the extent of the repression which shell or skin certainly does perform, let its nature be what had been exerted on the imprisoned gases up to the mo | it may, The exceeding definiteness of direction recog. ment of eruption. When a bullet is fired from a gun, the nized in the jets we have spoken of above is sufficient to velocity of its flight depends on the completeness with show that the crust bears sway, so to speak, over the inwhich before and during the passage of the bullet along ternal gaseous nucleus, and that the gases forming this the barrel, the escape of the gases resulting from the firing nucleus, though they escape, yet owe the energy of their of tbe gunpowder has been prevented. And although a outrush to the action of the enclosing shell. quantity of loose gunpowder can, in a sense, explode in The theory advanced by Professor Young seems exactly the open air, yet not only are the effects of explosion al- l suited to meet the difficulties here indicated, and to account together less marked than where the exploding matter for those more prominent solar phenomena with wbich has been confined, but the explosion takes place in no alone, at present, astronomers can hope to deal successfully. definite direction, but all around the place where fire had He considers that the sun has no permanent crust, nor in been applied. In order that matter may be propelled fact any envelope which can in the ordinary sense of the along some particular path there must, before explosion term be regarded as a crust at all. But inasmuch as the takes place, be an enclosing substance of some sort, the vaporous globe of the sun is in the presence of what Sir yielding of which at a particular point determines the John Herschel has called “the cold of space," a process direction in which the outrushing matter proceeds.
necessarily takes place over its whole outer surface corteAccordingly, both Zöllner and Respighi, in adopting | sponding to the formation of clouds in our skies, when the the general theory that the jet prominences are phenom. vapor of water bas risen to such a height as to be conena of eruption, although they held different opinions as densed into the form of visible cloud. The vapors of the to the cause of eruption, agreed in maintaining that the sun's globe consist in the main, we know, of the metallic el eruptions must take place through some substance forming | ements, and these metallic vapors would condense into a sort of solar crust. Zöllner held that the eruptions are clouds composed of minute globules (or perhaps vesicles) akin to terrestrial volcanic outbursts, Respighi considered of fluid metal. But such clouds would not usually remain that some kind of electrical action was in question ; but l in the simple cloud-form. They would be continually neither astronomer doubted that the eruptions sprung gathering with a rapidity of formation incomparably esfrom beneath a compact solid or liquid surface.
ceeding that which we recognize in our summer clouds, But there is one great difficulty in the assumption that | even when a great storm is approaching. They would bethe sun has a solid or liquid nucleus. The sun is a body come rain-clouds, the rain falling from them consisting whose density is very small by comparison with the earth's, simply of molten metals. More and more heavy would this and still more by comparison with the density we should metallic rain become as it descended, even as our own rains be led to expect from the consideration of the enormous are heavier at low levels than at considerable heights. Quite low down, and when approaching the region where | bright outer layer of clouds, from which metallic rains are the intense beat of the sun's interior would revaporize them, falling. The edge of the clouds would then define the outthe metallic rains would descend in perfect sheets, forming side of the spot's fringe like border, while the lower limits a nearly continuous liquid envelope.
of the shower would define the inside. It is true that this It will be well, however, to give Professor Young's own explanation assumes that the lower limits of the showers account of the theory, not only because it is always desira- | falling all round a spot lie closer than the upper ; but this ble in presenting views of the kind to avoid the risk of would naturally happen if, as is suggested by many circumfalse interpretation, but because in the present instance the stances, a spot is a scene where there is a cyclonic downsubject is one of so stupendous a nature, and surrounded rush of matter from without; for the whirling vapors would by such great difficulty, that the reader will do well to ex sway the upper parts of the downfalling streams more amine the new theory in more than one aspect : “ The effectively than the lower parts, which parts would thereeruptions which are all the time occurring on the sun's sur fore tend inwards towards the spot's central region. face,” says Professor Young, “almost compel the supposi. It will probably occur to the reader that if heavy solar tion that there is a crust of some kind which restrains the showers fell in this particular way, then, unless the showimprisoned gases and through which they force their way | ers were perfectly continuous (a most improbable contin. with great violence. This crust may consist of a more or gency) the edges of the shower regions thus brought into less continuous sheet of rain, not of water, of course, but of view should show streaks radiating from the direction of materials whose vapors are shown by means of the spectro the spot's centre. To explain our meaning more clearly, scope to exist in the solar atmosphere, and whose conden suppose a large region of the earth to be covered by rainsation and combinations are supposed to furnish the solar clouds from which showers are falling ; then suppose a heat. The continuous outflow of the solar heat is equiva circular part of the cloud-covering removed, and that the lent to the supply that would be developed by the conden- / rain falling all around this circular space slopes inward sation from steam to water of a layer about five feet thick, towards the middle of the space; now suppose a balloonist over the whole surface of the sun, per minute. As this tre- to ascend from the middle of the circular space until he mendous rain descends, the velocity of the falling drops is high above the level of the cloud-layer; then he would be retarded by the resistance of the denser gases would see below him a great opening in the cloud-layer underneath, the drops would coalesce until continuous ! (white in the sunlight, which would be shining on its outsheets would be formed, and the sheets would unite and side), and he would see all round the opening and within form a sort of bottomless ocean reating upon the compressed it the streams of falling rain, forming, as it were, a fringe vapors beneath, and pierced by innumerable ascending jets within the circular gap; and it is manifest that this fringe and bubbles. It would have nearly a constant depth in would show streaks in the direction of the falling rain thickness, because it would revaporate at the bottom nearly streams, that direction as seen by the balloonist appearing as fast as it would grow by the descending rains above, to be radial with respect to the circular openings. Now it though probably the thickness of this sheet would continu- | has long been noted as one of the most remarkable features ally increase at some slow rate, and its whole diameter of the solar spots that their penumbral fringes are streaked diminish. In other words, the sun, according to this view, precisely in this manner. is a gigantic bubble whose walls are gradually thickening But again, it will be seen that if falling solar showers and its diameter diminishing at a rate determined by its were thus thrust outwards at their upper edges, then loss of heat. It differs, however, from ordinary bubbles in since lines drawn towards a centre lie closer as the centre the fact that its skin is constantly penetrated by blasts is approached — the penumbra of a spot ought to be brighter and jets from within."
at its inner edge than at its outer. The difference would Professor Young proceeds to remark that “ the hypoth be rendered all the more remarkable because the showers esis leaves the question of the solar spots untouched, but is would grow heavier as they descended, according to the consistent witb either of those most in vogue at present." law observed in our rain-showers. Now here, again, it is Here, however, we have to note an interesting circumstance a noteworthy circumstance that long before the bubble tending to show that Professor Young's theory is one which theory of the sun had been invented, astronomers had accords better than any other with the phenomena pre- / recognized the fact that the penumbral fringe of a spot sented by the surface of the sun. Unknown to Professor is markedly darker on the outside than on the inside. Young 1 a theory not unlike his was suggested four or five The observation has been made in such a way as to preyears ago by Mr. Stoney, F. R. S., especially to explain clude the possibility that contrast alone would account the features presented by the solar spots. After carefully for the phenomenon. Thus a second and most remarkexamining the evidence, Stoney was led to the conclusion able feature of sun-spots finds its explanation in the new that the brightest parts of the sun (the bright granules) are theory. We venture, indeed, to say with some confidence regions where there are solar clouds and solar showers, the that the appearance in question suffices to throw serious less bright parts - on which the granules are seen as on a doubts upon all other theories which have hitberto been background - are regions wbere there are clouds but no propounded in explanation of sun-spot phenomena. We showers, and the penumbral parts of the spots are regions do not say that the bubble theory can be regarded as dewhere there are showers without cloud, that is, where we monstrated on the strength of this simple fact; but we are looking at the edge of a shower.
do assert that no theory hitherto put forward has given In fact, if we consider those features of the solar heat any account whatever of the peculiarity in question. which have been regarded as most characteristic as well as It is manifest, however, that Professor Young's theory most difficult to explain, we shall find reason for consider gives no explanation of the origin of sun-spots, nor does ing Professor Young's theory as affording a very satisfac the theory throw any light whatever on that perplexing tory explanation of the observed appearances. It has al subject. Nevertheless, it is impossible to consider the ways been regarded as a very remarkable circumstance that condition of the sun, as presented by the startling theory the outlines of sun-spots are well defined not only on the before us, without being led to reëxamine the questions inside, where the dark central part of the spot is, but also suggested by what we have learned respecting sun-spots. on the outside, where the spot adjoins on the bright surface We see confirmed by the theory the view to which asof the sun. But this peculiarity is explained at once, if we tronomers bad for some time been led, that spots are proregard the solar shell-envelope as consisting of a very duced by action exerted from without. We perceive 1 Professor Young communicated to the writer a sketch of his theory sev
reasons for believing that this action is one of great energy, eral weeks before he published it, inviting coraments and asking particularly its energy being probably in the main dynamical. It is whether any similar theory had been previously enunciated. A great pressure of engagements prevented the writer from replying at the time to this
true that the darkness of a spot must be explained by letter, otherwise the published statement of the theory would have con
physical considerations depending on the laws of heat and taiprd a reference to the facts mentioned in what follows. In any case, how light, and that chemical relations must be taken into acever, it is manifest that the views of Professor Young and of Mr. Stoney are independent of each other, being devised in explanation of two wholly dis
| count in dealing with the subject. But we seem to tinct sets of circumstances.
recognize clear evidence of the actual thrusting on one side of solar clouds with their down-pour of metallic rain, to the level of the sun's equator, according with the corre where spots are formed. Apart from the considerations sponding slant in the case of lines drawn from the spot-zones relating to the penumbral fringe of a spot, there is a mani. | to the centre of the sun's globe. Such a tendency has been fest heaping up of the solar cloud-layers all round a spot, discovered, though the assigned slant of the cometic orbits where the bright and elevated regions called faculæ are is somewhat greater than the theory requires. Let us be Been. Besides, many spots indicate by their shape and permitted to quote, notwithstanding the technicality of its changes of shape the action of most energetic forces, terms, a passage from Dunkin's excellent Appendix to breaking up and thrusting apart, as it were, the masses of Lardner's * Astronomy," in which this relation is stated : clouds which form the light giving surface of the sun.. “ There are evident indications of a tendency of the planes
Now the various theories, which have been formed to of the cometary orbits to collect around a plane whose inaccount for the periodic recurrence of spot-frequency, clination to the plane of the ecliptic is forty-five degrees ; have been based on influences supposed to be exerted in or if a cone be imagined to be formed, having a semi-angle some mysterious manner by the planets. In particular, | of forty-five degrees, and its axis at right angles to the Jupiter has been held responsible for the great spot- plane of the ecliptic, the planes of the cometary orbits beperiod of about eleven years. Jupiter's period of revo- | tray a tendency to take the position of tangent-planes to lution around the sun being about eleven years and the surface of such a cone.” We beg those of our readers ten inonths, it has been inferred that he regulates this who eschew cones, semi-angles, and tangent-planes, to trust period of spot-frequency; and a comparison has been made in our assurance that the sentence just quoted bears the between bis supposed action in this respect and the appar. meaning we have assigned to it. So far, then, the observed ent connection existing between our moon's motions and relations among cometic orbits seem to accord with the the recurrence of terrestrial volcanic action. It is mani idea that the meteoric stragglers following on the track of fest that the explanation (if such it can be called) thus comets may be in some way the cause of solar spots. indicated would correspond with a theory presenting sun. But we might also expect, if this theory were the true spots as caused by solar forces acting from within outwards, one, that some great comet which had approached the son but would by no means accord with a theory indicating as very nearly would give evidence in favor of the theory. the source 1 of solar spots an action exerted from without For we could hardly but suppose that such a comet would the solar orb. Moreover, we cannot readily overlook the be followed by very large meteoric attendants, and we might circumstance that the eleven-year spot-period does not expect to find some one or other of these not passing like accord exactly with Jupiter's period of revolution. In the parent comet quite clear of the sun, and accordingly consequence of this want of agreement, we have not to go occasioning (if the theory be true) a great spot. Such erfar back to find periods when spots have been very idence would be particularly striking if it occurred at a numerous, corresponding with the time when Jupiter has time almost midway between two epochs when spots bad been at bis nearest to the sun, farthest from the sun, and been very numerous. Now, a comet once appeared which at his mean distance. This appears to render altogether | made a singularly near approach to the sun's surface. untenable the theory that there is any connection wbatever This was the comet of 1843, which Sir John Herschel thus between Jupiter's distance from the sun and the appear graphically describes : “Many, I dare say, remember its ance of spots upon the sun's surface. And if we give up immense tail, which stretched half-way across the sky after the theory that Jupiter influences the sun in this manner, sunset in March of that year. But its head, as we bere it seems impossible to believe in planetary influence at all. saw it, was not worthy of such a tail. Farther south, hor. So that we may regard ourselves as free to search for ever, it was seen in great splendor. I possess a picture by other causes, and especially for the possible existence of Professor Piazzi Smyth, Astronomer. Royal of Scotland, of matter reaching the sun from time to time from without, its appearance at the Cape of Good Hope, which repreand so producing those openings.
sents it with an immensely long, brilliant, but very slender Thus viewing the matter, one might be led to suspect and forked tail. Of all the comets on record, that ap the existence of some as yet undetected comet with its proached nearest the sun. Indeed, it was at first supposed train of exceptionally large meteoric masses, travelling in that it had actually grazed the sun's surface, but it proved a period of about eleven years around the sun, and having to have just missed by an interval of pot more than 80,000 its place of nearest approach to that orb so close to the miles, about a third of the distance of the moon from the solar surface that when the main flight is passing the strag earth, which (in such a matter) is a very close shave inglers fall upon the sun's surface. But then there is this deed to get clear off. There seems very considerable rea. difficulty, that the spots appear always on two zones of the son to believe that this comet has figured as a great comet sun's surface, corresponding in a general sense to the tem on many occasions in history; and especially in the year perate zones on the surface of the earth, and though it | 1668, when just such a comet, with the same remarkable would be easy to account for one such zone by the sug peculiarity, of a comparatively feeble head and an immense gested comet theory, the existence of two is not so readily train, was seen at the same season of the vear, and in the accounted for.
very same situation among the stars. Thirty-five years has And yet though no single comet can be accepted in ex been assigned with considerable probability as its period planation of the observed facts, there are some circum of return, but it cannot be regarded as quite certain." stances which, so soon as the general idea of cometic influ Now, this remarkable comet having passed thus close to ence has been mooted, attract our attention as favoring the sun, in the year 1843, which was very nearly the time that theory. For example, if we ascribed the sun's spots
we ascribed the sun's spots of fewest spots, 2 afforded precisely such an opportunity for to comets, we should require that many comets should testing the comet theory of sun-spots as we have indicated have paths carrying them very close to the sun's surface; above. This would be a time when we should expect no and though few such comets have been detected, yet the large spot to make its appearance, for it has been observed laws observed in the paibs of discovered comets indicate that the larger spots occur at or near the time when spots that if we only had an equal chance of detecting comets
had an equal chance of detecting comets are most numerous. But Professor Kirkwood (of Bloomi. which passed very near to the sun, they would be found to lington, Indiana, U. S.) has called attention to the fact be very numerous indeed. It has been shown that, if a that « one of the largest and most remarkable spots ever model of the solar system were constructed and a material seen on the sun's disk appeared in June, 1843, and continparticle were set to indicate tbat point of each cometic path ued visible to the naked eye for seven or eight days. The wbich lies nearest to the sun, the density with which such diameter of this spot was, according to Schwabe, 74,000 particles would be aggregated would be found to increase miles, so that its area was many times greater than that of rapidly in approaching the sun.
Again, since there are two zones of sun-spots, we should 2 This will be manifest from the following numbers, indicating how many expect to find the cometic paths showing an average slant
new spots were observed in the years between 1836 and 1819: In 1835
272: in 1837, 333: in 1838, 282; in 1839, 162: in 1840, 152; in 1841, 102; 1 We emphasize the word "source," because whatever opinion may be in 1842, 68: in 1913, 34; in 1844, 52; in 1815, 114: in 1848, 157; in 1847, formed as to the origin of sun.spots, no doubts can be entertained respect- 257 : in 1848, 339 ; and in 1849, 239. We thus see that 1837 and 1845 went ing the action of expicsive solar forces.
years of greatest spot-frequency, while 1843 was a year of least spot-frequency